Re: [PATCH 1/3] riscv: optimized memcpy

[Matteo Croce]

On Wed, Jun 16, 2021 at 1:46 PM Guo Ren <guoren@xxxxxxxxxx> wrote:
>
> Hi Matteo,
>
> Have you tried Glibc generic implementation code?
> ref: https://lore.kernel.org/linux-arch/20190629053641.3iBfk9-I_D29cDp9yJnIdIg7oMtHNZlDmhLQPTumhEc@z/#t
>
> If Glibc codes have the same performance in your hardware, then you
> could give a generic implementation first.
>

Hi,

I had a look, it seems that it's a C unrolled version with the
'register' keyword.
The same one was already merged in nios2:
https://elixir.bootlin.com/linux/latest/source/arch/nios2/lib/memcpy.c#L68

I copied _wordcopy_fwd_aligned() from Glibc, and I have a very similar
result of the other versions:

[  563.359126] Strings selftest: memcpy(src+7, dst+7): 257 Mb/s

Regards,
-- 
per aspera ad upstream